Attempting 3/4" plank solid maple over suspended concrete at ground level (parikng garage beneath) 700 sf

Any suggestions would be helpful. The site: www.learnflooring.com hosted by Bill Harte......does anyone have any comments on how valid this site is for the information being offered for $37 us.

This site has been very helpful. This is what I intend to do. Any comments are appreciated.

Power fasten (Hilti) and glue 3/4 "plywood to concrete. Can I float the pywood instead? Or just glue it. My concrete is sealed and acid washed so I will need to remove the sealer and rough up the concrete with course grit sandpaper.

By power fastening the plywood I will damage any vapour barrier I put down hence floating or gluing the plywood is this a solid option.

What is the best way to deal with concrete leveling issues or will the plywood eliminate some of the highs and lows?

Should the 3/4" plywood be rated for outdoor use?

Is leaving a 1/4" space around the perimeter and 1/8 space between the plywood joints acceptable?

Thank you

Bob
Vancouver Canada

Yes, you can install a floating subfloor. The best one and way is to screw two sheets of 1/2" CDX together in opposing dirctions.

Flatten the concrete first by grinding down the highs and filling the lows. Use a cementious concrete patch: Plani-patch by Mapei
For a floating subfloor, an 8 mil polyethylene plastic vapor barrier works well. For a glued down subfloor, consider Bostik's MVP barrier then and Bostik's BST adhesive. Cut 3/4" CDX plywood into 16" x 8' panels and install at 90 degrees (right angle) to the direction of the floors.

It should "X" rated, for exterior, as in CDX

Is leaving a 1/4" space around the perimeter and 1/8 space between the plywood joints acceptable?

No. Leave 3/4" around the perimeter of the plywood subfloor and gap 1/4" between panels.

Read this:
http://www.nofma.org/Portals/0/Publicat ... 010_04.pdf
http://www.nofma.org/Portals/0/Publicat ... 010_03.pdf
http://www.nofma.org/Portals/0/Publicat ... 9_03.pdfIs [/quote]

Gary

Thank you for your reply very helpful. Floating on 2 - 1/2" Plywood sheets makes the job a lot easier. Makes a lot of sence.

Bob

Nailing Maple planks to floating plywood ( 2 1/2" sheets) over 8" concrete. Using staple gun powered by copressor.

Half a room done going well. A little squishy but good and tight.